Search

Residential wood burning is becoming an increasingly important cause of air quality problems since it has become a popular source of alternative energy to fossil fuel. In order to characterize the contribution of residential wood burning to local particle pollution, a field campaign was organized at the village of Seiffen (Saxony, Germany). During this campaign, an Aerosol Mass Spectrometer (AMS) was deployed in parallel to a PM1 high volume filter sampler. The AMS mass spectra were analyzed using Positive Matrix Factorization (PMF) to obtain detailed information about the organic aerosol (OA). Biomass-burning organic aerosol (BBOA), Hydrocarbon-like organic aerosol (HOA), and Oxygenated Organic Aerosol (OOA) were identified and represented 20 %, 17% and 62% of total OA, respectively. Additionally, Polycyclic Aromatic Hydrocarbons (PAH) were measured by the AMS with an average concentration of 10 ngm-3 and short term events of extremely high PAH concentration (up to 500 ngm-3) compared to the mean PAH value were observed during the whole measurement period. A comparison with the results from PM1 filter samples showed that the BBOA factor and the AMS PAH are good indicators of the total concentration of the different monosaccharide anhydrides and PAH measured on the filter samples. Based on its low correlation with CO and the low car traffic, the HOA factor was considered to be related to residential heating using liquid fuel. An influence of the time of the week (week vs. weekend) on the diurnal profiles of the different OA components was observed. The weekdays were characterized by two maxima; a first one early in the morning and a stronger one in the evening. During the weekend days, the different OA components principally reached only one maximum in the afternoon. Finally, the PAH emitted directly from residential wood combustion was estimated to represent 1.5% of the total mass of the BBOA factor and around 62%of the total PAH concentration measured at Seiffen. This result highlights the important contribution of residential wood combustion to air quality and PAH emissions at the sampling place, which might have a significant impact on human health. Moreover, it also emphasizes the need for a better time resolution of the chemical characterization of toxic particulate compounds in order to provide more information on variations of the different sources through the days as well as to better estimate the real human exposure. [ABSTRACT FROM AUTHOR]

The fractions of local traffic (LT), urban background (UBG) and regional background (RBG) of the particle pollution at a traffic-influenced kerbside in Dresden, Germany, were determined by measurements of size-segregated mass concentration, chemical composition and particle size distributions in a network of five measurement stations partly existing and partly set up for this study. Besides the kerbside station, one urban background site and three rural sites were included in the study. Using data from these different sites, the LT, UBG, and RBG contributions were calculated, following the approach of Lenschow et al. (). At the kerbside site, 19% of the total number concentration (Dp = 10-600 nm) could be attributed to the RBG, 15% to the UBG, and 66% to the LT immediately nearby. Particle mass concentrations up to Dp = 420 nm RBG amounts to 68%, UBG to 21%, and LT only to 11%. Highest mass concentrations were observed at all stations in autumn and winter during easterly inflow directions. The local traffic fraction of PM mass at the kerbside station was found to be 30% for westerly inflow, but only 7% for southeasterly inflow due to the dominating transport fraction from up to 80% of the particle mass at this inflow direction. Size-resolved investigation showed the main fractions in both the particle size ranges of Dp = 0.42 to 1.2 and 0.14 to 0.42 μm at all stations. The main components sulphate, ammonium and total carbon showed higher concentrations at south-eastern/eastern inflow in autumn at all stations, while nitrate at the kerbside and urban background site was higher during westerly inflow in winter. The chemical composition at the regional background site at westerly inflow (12% nitrate, 8% sulphate, 11% total carbon) was significantly different from that at easterly inflow (3% nitrate, 15% sulphate, 22% total carbon). The prevailing part of the ionic mass was always found in the fine particle range of Dp = 0.14 to 1.2 μm at all stations. For all inflow directions highest total carbon concentrations were observed at the kerbside station, especially in the ultra-fine size range of Dp = 0.05 to 0.14 μm with up to 30% of the whole carbon. PAH concentrations were always higher at south-eastern/eastern inflow especially during wintertime. Trace metal components and silicon were found mainly in the coarse mode fraction at the kerbside resulting from abrasion or resuspension. [ABSTRACT FROM AUTHOR]

Abstract: The size-segregated chemical composition of atmospheric aerosol particles (aerodynamic diameter Dpaer = 0.05–10 μm) was studied to reveal differences between seasons (winter/summer), air mass origins (East/West/North), and days of the week (weekday/Sunday). The goal was to identify the different particle emission sources for the first time at a kerbside in the city of Dresden, Germany. Ultra-fine particles (Dpaer = 0.05–0.14 μm, 12% of PM10) consisted of approximately 80% OM (organic matter) and EC (elemental carbon), while fine particles (Dpaer = 0.14–1.2 μm) comprised about 55% ionic compounds with 44% OM and EC. The coarse fraction (Dpaer = 1.2–10 μm) consisted of approximately 65% ions/OM/EC and 20% metal oxides. Pb, Zn, and Cu showed crustal enrichment factors (CEFSi) > 100 for all particle sizes indicating strong anthropogenic influence. The Zn source was coal burning rather than traffic emissions. Doubled concentrations in winter were likely caused by coal combustion (Pb) and biomass burning (K), but also by a lower mixing layer height. Air masses from the East caused higher Pb and K concentrations. The origin of air masses had almost no influence on Cu, Cr, Fe, Mn, Zn and Ca, Si, Ti, indicating local sources such as traffic and heating. Possible actions against particle emissions are discussed. [Copyright &y& Elsevier]

Atmospheric aerosol particle size distributions at a continental background site in Eastern Germany were examined for a one-year period. Particles were classified using a twin differential mobility particle sizer in a size range between 3 and 800 nm. As a novelty, every second measurement of this experiment involved the removal of volatile chemical compounds in a thermodenuder at 300°C. This concept allowed to quantify the number size distribution of nonvolatile particle cores - primarily associated with elemental carbon, and to compare this to the original non-conditioned size distribution. As a byproduct of the volatility analysis, new particles originating from nucleation inside the thermodenuder can be observed, however, overwhelmingly at diameters below 6 nm. Within the measurement uncertainty, every particle down to particle sizes of 15 nm is concluded to contain a non-volatile core. The volume fraction of non-volatile particulate matter (non-conditioned diameter <800 nm) varied between 10 and 30% and was largely consistent with the experimentally determined mass fraction of elemental carbon. The average size of the non-volatile particle cores was estimated as a function of original non-conditioned size using a summation method, which showed that larger particles (>200 nm) contained more non-volatile compounds than smaller particles (<50 nm), thus indicating a significantly different chemical composition. Two alternative air mass classification schemes based on either, synoptic chart analysis (Berliner Wetterkarte) or back trajectories showed that the volume and number fraction of non-volatile cores depended less on air mass than the total particle number concentration. In all air masses, the non-volatile size distributions showed a more and a less volatile ("soot") mode, the latter being located at about 50 nm. During unstable conditions and in maritime air masses, smaller values were observed compared to stable or continental conditions. This reflects the significant emission of non-volatile material over the continent and, depending on atmospheric stratification, increased concentrations at ground level. [ABSTRACT FROM AUTHOR]

Abstract: Hill cap cloud field experiments were performed during autumn 2001 and 2002 in the Thüringer Wald (Germany). Gas phase trace compounds were determined at an upwind, summit, and downwind sites and major particulate components at an upwind and downwind site. Cloud water and total cloud components (drop residuals and interstitial particles) were determined at a summit site. Three events were fulfilling the criteria for the best conditions defined by during a connected flow upwind–summit–downwind sites and further detailed analysis was performed on these events. Cloud water components were compared with particle concentration at upwind and downwind site. The concentrations of non-volatile components in cloud water were found to be in good agreement with corresponding particle phase concentrations at the upwind site. Downwind site particulate component concentrations of non-volatile compounds were lower than in cloud water indicating loss processes during transport such as deposition. The concentrations of volatile components were found to be higher in cloud water than in the particle phase concentrations at up- and downwind site samples probably due to a loss from impactor sampling technique as well as a transport loss. Indications for changes of aerosol composition by cloud processes were found from a limited number of cases. Elevated sulphate and ammonium concentrations from upwind to downwind site in the smallest particle size range (PM0.05–0.14) were found during event I (20% and 17%) and event III (70% and 150%), respectively. In the particle size range of PM0.14–0.42 an increase of OC by about 20% for event I was observed. Considering the relative contributions of components to the single size range mass (avoiding physical sink processes), comparatively higher increases for sulphate, nitrate, ammonium, OC, and EC could be observed. Indications of an increase of aerosol mass can be derived in some cases from the aerosol number and volume size distributions. Results from a complex multiphase model (SPACCIM) are consistent showing an increase in concentrations of some compounds for some cases. [Copyright &y& Elsevier]

Abstract: This contribution presents characterisation efforts of the gas phase and particle phase main components during the FEBUKO orographic cloud passage experiments in autumn 2001 and 2002 in the Thüringer Wald (Germany). Three events out of a total of 14 were chosen as the best events considering all meteorological conditions. Gas phase and size-segregated particle phase data obtained from physical (dry size distribution) and chemical (particle mass, main ions, OCEC, and water-soluble metals) measurements are presented for the upwind site. The total particulate mass concentration (PM10) was found to be between 8 and 17μgm−3. Particles with an aerodynamic diameter up to 1.2μm contribute about 80% of the mass concentration. About 90% of the total ion concentration consists of nitrate, sulphate and ammonium. The OC concentration in all three events amounts to about 1.0μgm−3, whereas EC concentrations were between 0.40 and 1.0μgm−3. The contribution of OC and EC to stage mass ranged from 5% to 35% and from 2% to 17%, respectively. The water content of particles was estimated to be 16–18%. Physical and chemical mass closure is discussed in detail and the results are in a reasonable agreement. The complex data set obtained for each event can be used in the initialisation of models for the multiphase processes during and after the cloud passage of the characterised air mass. [Copyright &y& Elsevier]

For a period of 10 years (1993–2002) daily PM10 samples were collected on quartz filters by a PM10 high-volume sampler (Sierra-Andersen). In addition, since 1995 weekly filter samples of PM10, PM2.5 and since 1999 PM1 filter samples were collected by a low-volume sampler (‘Partisol 2000’, Rupprecht and Patashnik) on Teflon filters at the IfT research station Melpitz (12°56′E, 51°32′N) located in the downwind plume of the Leipzig conurbation in central Europe. The resulting time series were compared based on weekly means (particle mass r=0.90, NO3- mass r=0.94, SO42- mass r=0.92 and NH4+ mass r=0.90) and integrated in a historical mass trend (since 1983) for Saxony. In the data (1983–1990) the total particle mass concentration (TSP) shows big scatter with a mean of about 75μgm-3. Since the re-unification of Germany in 1990 a decrease in PM10-concentration to a mean of 20–30μgm-3 is observed. The mass concentration of PM10 shows a decreasing trend from a yearly maximum value in 1996 (39μgm-3) to a mean value for 1999–2002 of about 23μgm-3. The highest values were observed just before the winter of 1997/1998. No pronounced concentration peaks were found in the following winters. Reasons are the rapid modernization of power plants and the decreasing number of coal heating systems in the Leipzig conurbation and its surroundings as well as a lack of strong inversion situations. The NO3-/SO42--ratio shows a typical increasing trend caused by the decreasing SO42--mass concentration in PM10 which originates in the dramatic decrease of SO2 concentrations. From the weekly low-volume samples the mass contributions of PM1, PM2.5–PM1 and PM10–PM2.5 to PM10 (100%) for 1999–2002 were about 61%, 20% and 19% for winter and 42%, 13% and 45% for summer, respectively. Most of the PM2.5 mass is PM1. During summers the weekly ratio of coarse particles (PM10–PM2.5) to fine particles (PM2.5) was higher (about 1.4) than the winter value (about 0.3). An additional impactor for PM1 at the low-volume sampler contains a quartz filter for the weekly determination of organic carbon (OC) and elemental carbon (EC) using a thermographic method. About 30% of the PM1 mass is total carbon (TC=OC+EC). The percentage of EC to TC seems to be increasing in the summer from 1999 to 2002. [Copyright &y& Elsevier]

Abstract: An overview of the two FEBUKO aerosol–cloud interaction field experiments in the Thüringer Wald (Germany) in October 2001 and 2002 and the corresponding modelling project MODMEP is given. Experimentally, a variety of measurement methods were deployed to probe the gas phase, particles and cloud droplets at three sites upwind, downwind and within an orographic cloud with special emphasis on the budgets and interconversions of organic gas and particle phase constituents. Out of a total of 14 sampling periods within 30 cloud events three events (EI, EII and EIII) are selected for detailed analysis. At various occasions an impact of the cloud process on particle chemical composition such as on the organic compounds content, sulphate and nitrate and also on particle size distributions and particle mass is observed. Moreover, direct phase transfer of polar organic compound from the gas phase is found to be very important for the understanding of cloudwater composition. For the modelling side, a main result of the MODMEP project is the development of a cloud model, which combines a complex multiphase chemistry with detailed microphysics. Both components are described in a fine-resolved particle/drop spectrum. New numerical methods are developed for an efficient solution of the entire complex model. A further development of the CAPRAM mechanism has lead to a more detailed description of tropospheric aqueous phase organic chemistry. In parallel, effective tools for the reduction of highly complex reaction schemes are provided. Techniques are provided and tested which allow the description of complex multiphase chemistry and of detailed microphysics in multidimensional chemistry-transport models. [Copyright &y& Elsevier]

Background: Left ventricular conduction disturbances (VCD) with or without need for pacemaker (PM) implantation are common after transcatheter aortic valve replacement (TAVR). Its effect on patients' functional recovery after TAVR is unclear., Methods and Results: 212 patients (Age 80.8 ± 6.4 years, logEuroscore 28.95 ± 17.37 %) underwent TAVR with the self-expanding CoreValve prosthesis and completed 9-month follow-up (FU). After TAVR 125 (59 %) patients were diagnosed with VCD. This group consists of 41 (19 %) patients with a new PM after TAVR, 33 (16 %) patients with PM prior TAVR and markedly increased ventricular stimulation rate, 48 (23 %) patients with new LBBB post-TAVR and three (1 %) patients with LBBB prior TAVR. After FU, the presence of VCD alone was associated with worse recovery of left ventricular ejection fraction (LVEF) (VCD: LVEFbaseline 51.7 ± 18.2 %, LVEFFU 53.9 ± 13.0 %; p = 0.8; noVCD: LVEFbaseline 53.8 ± 12.9 %, LVEFFU 63.4 ± 10.1 %; p < 0.01) but had no impact on functional outcomes after TAVR (p > 0.05). Especially patients with VCD caused by permanent RV pacing showed worse functional outcomes presenting with higher functional NYHA classes (p < 0.05), and higher NT-proBNP levels (p < 0.05). 20.4 % of patients with need for PM after TAVR remained in NYHA class ≥3, as compared to 5 % of patients without PM (VCD but no PM: 4.7 %, p < 0.001; noVCD: 5.3 %, p < 0.001). VCD with or without need for PM had no impact on survival after FU., Conclusion: The occurrence of VCD after TAVR is common and associated with unfavorable left ventricular functional recovery. However, only the combination of VCD with permanent right ventricular pacing has adverse impact on heart failure-related symptoms after TAVR.

We studied the mass-related aerosol properties, simultaneously at two sites at the urban roof top level in the same city. No systematic influence of the wind vector on the difference in the aerosol concentrations between the two locations could be found. These results are compared with results from a second, similar experiment over a larger distance including one urban and one rural site. Surprisingly, we could not detect a tendency which would indicate that sampling air at distance in the order of 1 km would be less affected by the heterogeneity than sampling distanced in the order of 10 km apart. On the contrary, the results suggest that mass-related properties at two sites in the same city are not necessarily more similar than at an urban and a rural site outside the city. These results stress the limited horizontal homogeneity of urban atmospheric aerosol. As a conclusion it is suggested that single-site measurements of mass-related aerosol properties should be considered to be representative for an area smaller than 1 km2 on size.